Wooyoung Jang

1,25-Dyhydroxyvitamin D3 attenuates rotenone-induced neurotoxicity in SH-SY5Y cells through induction of autophagy

BACKGROUND AND OBJECTIVES Dysregulation of the autophagy pathway has been suggested as an important mechanism in the pathogenesis of Parkinsons disease (PD). Therefore, modulation of autophagy may be a novel strategy for the treatment of PD. Recently, an active form of vitamin D₃ has been reported to have neuroprotective properties. Therefore, we investigated the protective, autophagy-modulating effects of 1,25-dyhydroxyvitamin D₃ (calcitriol) in an in vitro model of Parkinsons disease. METHODS An in vitro model of Parkinsons disease, the rotenone-induced neurotoxicity model in SH-SY5Y cells was adapted. We measured cell viability using an MTT assay, Annexin V/propidium iodide assay, and intracellular reactive oxygen species levels and analyzed autophagy-associated intracellular signaling proteins by Western blotting. RESULTS Rotenone treatment of SH-SY5Y cells reduced their viability. This treatment also increased reactive oxygen species levels and decreased levels of intracellular signaling proteins associated with cell survival; simultaneous exposure to calcitriol significantly reversed these effects. Additionally, calcitriol increased levels of autophagy markers, including LC3, beclin-1, and AMPK. Rotenone inhibited autophagy, as indicated by decreased beclin-1 levels and increased mTOR levels, and this effect was reversed by calcitriol treatment. DISCUSSION Calcitriol protects against rotenone-induced neurotoxicity in SH-SY5Y cells by enhancing autophagy signaling pathways such as those involving LC3 and beclin-1. These neuroprotective effects of calcitriol against rotenone-induced dopaminergic neurotoxicity provide an experimental basis for its clinical use in the treatment of PD.

Safety and efficacy of recombinant human erythropoietin treatment of non-motor symptoms in Parkinson's disease.

BACKGROUND Numerous animal studies and clinical trials have demonstrated that erythropoietin (EPO) has therapeutic effects in ischemic and degenerative diseases. However, few clinical trials have investigated the effect of EPO in Parkinsons disease (PD) patients. This study was an exploratory pilot study to investigate the effects of recombinant human EPO (rhEPO) on motor and non-motor symptoms (NMS) in PD patients. METHODS A total of 26 PD patients at the Hanyang University Hospital were enrolled in the study. The participants were randomly assigned to rhEPO and placebo groups. The rhEPO group was infused intravenously (40,000 IU each) twice a week for 5 weeks. Clinical improvement was estimated using the Unified Parkinsons Disease Rating Scale-III (UPDRS-III), the NMS Scale (NMSS) and the 39-Item Parkinsons Disease Questionnaire (PDQ-39). [(18)F] N-(3-fluoropropyl)-2β-carbon ethoxy-3β-(4-iodophenyl) nortropane (FP-CIT) photon emission tomography (PET) scanning was performed on each participant at baseline and again after 12 months. RESULTS The rhEPO administration significantly improved the NMSS and PDQ-39 scores at 12 months. The UPDRS-III, which reflects motor function, did not change significantly after the rhEPO treatment. With the NMSS, the domains of cardiovascular autonomic function, sleep/fatigue, mood/cognition and attention/memory showed significant changes. None of the participants experienced any serious adverse effects. DISCUSSION We found that rhEPO had beneficial effects on NMS but not on motor function. Dopaminergic refractory NMS, such as cardiovascular autonomic dysfunction and cognition, showed improvement after the administration of rhEPO. Our results suggest that rhEPO might be a good candidate for the treatment of NMS in PD patients.

1,25-dyhydroxyvitamin D3 Attenuates l-DOPA-Induced Neurotoxicity in Neural Stem Cells

The neurotoxicity of levodopa (l-DOPA) on neural stem cells (NSCs) and treatment strategies to protect NSCs from this neurotoxicity remain to be elucidated. Recently, an active form of vitamin D3 has been reported to display neuroprotective properties. Therefore, we investigated the protective effect of 1,25-dyhydroxyvitamin D3 (calcitriol) on l-DOPA-induced NSC injury. We measured cell viability via the cell counting kit-8 (CCK-8) and lactate dehydrogenase (LDH) assays and Annexin V/PI staining followed by flow cytometry, cell proliferation using the BrdU and colony-forming unit (CFU) assays, cell differentiation via immunocytochemistry, the levels of free radicals via 2′,7′-dichlorodihydrofluorescein diacetate (DCFH-DA) staining, apoptosis via DAPI and TUNEL staining, and intracellular signaling protein expression via Western blot. Antibody microarrays were also employed to detect changes in the expression of prosurvival- and death-related proteins. Treatment of NSCs with l-DOPA reduced their viability and proliferation. This treatment also increased the levels of free radicals and decreased the expression levels of intracellular signaling proteins that are associated with cell survival. However, simultaneous exposure to calcitriol significantly reduced these effects. The calcitriol-mediated protection against l-DOPA toxicity was blocked by the phosphoinositide 3-kinase (PI3K) inhibitor LY294004. l-DOPA also inhibited the expression of Nestin and Ki-67, and co-treatment with calcitriol alleviated these effects. The expression levels of GFAP, DCX, and Tuj1 were not significantly affected by treatment with l-DOPA or calcitriol. Calcitriol protects against l-DOPA-induced NSC injury by promoting prosurvival signaling, including activation of the PI3K pathway, and reducing oxidative stress.

The Neuroprotective Effect of Erythropoietin on Rotenone-Induced Neurotoxicity in SH-SY5Y Cells Through the Induction of Autophagy.

Currently, the autophagy pathway is thought to be important for the pathogenesis of Parkinson’s disease (PD), and the modulation of autophagy may be a novel strategy for the treatment of this disease. Erythropoietin (EPO) has been reported to have neuroprotective effects through anti-oxidative, anti-apoptotic, and anti-inflammatory mechanisms, and it has also been shown to modulate autophagy signaling in an oxygen toxicity model. Therefore, we investigated the effects of EPO on autophagy markers and evaluated its neuroprotective effect on rotenone-induced neurotoxicity. We adapted the rotenone-induced neurotoxicity model to SH-SY5Y cells as an in vitro model of PD. We measured cell viability using MTT and annexin V/propidium iodide assays and measured intracellular levels of reactive oxygen species. Immunofluorescence analysis was performed to measure the expression of LC3 and α-synuclein. Intracellular signaling proteins associated with autophagy were examined by immunoblot analysis. EPO mono-treatment increased the levels of mammalian target of rapamycin (mTOR)-independent/upstream autophagy markers, including Beclin-1, AMPK, and ULK-1. Rotenone treatment of SH-SY5Y cells reduced their viability, increased reactive oxygen species levels, and induced apoptosis and α-synuclein expression, and simultaneous exposure to EPO significantly reduced these effects. Rotenone enhanced mTOR expression and suppressed Beclin-1 expression, indicating suppression of the autophagy system. However, combined treatment with EPO restored Beclin-1 expression and decreased mTOR expression. EPO protects against rotenone-induced neurotoxicity in SH-SY5Y cells by enhancing autophagy-related signaling pathways. The experimental evidence for the EPO-induced neuroprotection against rotenone-induced dopaminergic neurotoxicity may significantly impact the development of future PD treatment strategies.

Autophagic modulation by rosuvastatin prevents rotenone-induced neurotoxicity in an in vitro model of Parkinson's disease.

Statins have been reported to have neuroprotective effects through anti-oxidant, anti-apoptotic, and anti-inflammatory mechanisms, and statin can also modulate autophagic signaling in an oxygen-toxicity models. Therefore, we investigated the effects of statin on autophagy markers and evaluated the neuroprotective effect of rosuvastatin against rotenone-induced neurotoxicity. As an in vitro model of Parkinsons disease(PD) we adopted the rotenone-induced neurotoxicity model in SH-SY5Y cells. Cell viability was measured using the MTT assay, and to detect the expression of LC3 and α-synuclein, immunofluorescence analysis was performed. Intracellular signaling proteins associated with autophagy were explored via immunoblotting. Treatment with rosuvastatin alone increased the levels of mTOR-independent/upstream autophagy markers, including Beclin-1 and AMPK. Rotenone treatment of SH-SY5Y cells reduced their viability and α-synuclein expression; simultaneous exposure to rosuvastatin significantly restored these parameters. Rotenone enhanced mTOR expression and suppressed Beclin-1 expression, indicating suppression of the autophagic system. However, combined treatment with rosuvastatin also restored the Beclin-1 expression and decreased mTOR expression. We demonstrated the neuroprotective effect of statin in SH-SY5Y cells against rotenone-induced neurotoxicity, as well as the modulation of ɑ-synuclein expression. The neuroprotective mechanism is likely to be associated with enhanced autophagy. The neuroprotective effect of statin on rotenone-induced dopaminergic neurotoxicity with modulation of autophagy provides a new therapeutic strategy for the treatment of PD.

Vitamin D deficiency in Parkinson's disease patients with orthostatic hypotension

The purpose of our study was to investigate the associations between serum vitamin D3 levels and orthostatic hypotension (OH) in patients with Parkinsons disease (PD).

Biochemical protective effect of 1,25-dihydroxyvitamin D3 through autophagy induction in the MPTP mouse model of Parkinson's disease.

In our previous study, the neuroprotective effect of calcitriol was confirmed in SH-SY5Y cells. In this article, we explored whether calcitriol showed neuroprotection in a subchronic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mouse model of Parkinson’s disease. After mice were treated with MPTP alone or cotreated with MPTP and calcitriol, the substantia nigra pars compacta was dissected, and related protein levels were detected by western blot. Our results suggest that the MPTP-injected mice treated with calcitriol had attenuated tyrosine hydroxylase expression and increased LC3-II conversion compared with those that were not. Above all, calcitriol showed neuroprotection in the MPTP mouse model.

Central cholinergic dysfunction could be associated with oropharyngeal dysphagia in early Parkinson’s disease

Dysphagia is an important issue in the prognosis of Parkinson’s disease (PD). Although several studies have reported that oropharyngeal dysphagia may be associated with cognitive dysfunction, the exact relationship between cortical function and swallowing function in PD patients is unclear. Therefore, we investigated the association between an electrophysiological marker of central cholinergic function, which reflected cognitive function, and swallowing function, as measured by videofluoroscopic studies (VFSS). We enrolled 29 early PD patients. Using the Swallowing Disturbance Questionnaire (SDQ), we divided the enrolled patients into two groups: PD with dysphagia and PD without dysphagia. The videofluoroscopic dysphagia scale (VDS) was applied to explore the nature of the dysphagia. To assess central cholinergic dysfunction, short latency afferent inhibition (SAI) was evaluated. We analyzed the relationship between central cholinergic dysfunction and oropharyngeal dysphagia and investigated the characteristics of the dysphagia. The SAI values were significantly different between the two groups. The comparison of each VFSS component between the PD with dysphagia group and the PD without dysphagia group showed statistical significance for most of the oral phase components and for a single pharyngeal phase component. The total score on the VDS was higher in the PD with dysphagia group than in the PD without dysphagia group. The Mini-Mental State Examination and SAI values showed significant correlations with the total score of the oral phase components. According to binary logistic regression analysis, SAI value independently contributed to the presence of dysphagia in PD patients. Our findings suggest that cholinergic dysfunction is associated with dysphagia in early PD and that an abnormal SAI value is a good biomarker for predicting the risk of dysphagia in PD patients.

Waveform analysis of tremor may help to differentiate Parkinson's disease from drug-induced parkinsonism

In this study, we analyzed the waveform characteristics of resting tremor by accelerometer recordings in patients with drug-induced parkinsonism (DIP) and Parkinsons disease (PD). We prospectively recruited 12 patients with tremulous PD and 12 patients with DIP presenting with resting tremor. Tremor was recorded from the more affected side and was recorded twice for a 60 s period in each patient. Peak frequency, amplitude and all harmonic peaks were obtained, and the asymmetry of the decay of the autocorrelation function, third momentum and time-reversal invariance were also computed using a mathematical algorithm. Among the parameters used in the waveform analysis, the harmonic ratio, time-reversal invariance and asymmetric decay of the autocorrelation function were different between PD and DIP at a statistically significant level (all p < 0.01). The total harmonic peak power and third momentum in the time series were not significantly different. The clinical characteristics of DIP patients may be similar to those of PD patients in some cases, which makes the clinical differentiation between DIP and PD challenging. Our study shows that the identification of parameters reflecting waveform asymmetry might be helpful in differentiating between DIP and PD.

Bedside cognitive assessments and falls risk in Parkinson's disease.

Cognitive deficits may contribute to falls in Parkinson’s disease (PD) and these deficits may be risk factors for falls. However, their association with falls has been generally studied in patients with continuous gait problems. There have been few studies in PD patients without postural instability. In addition, the effectiveness of various simple bedside cognitive tests in predicting falls has not been established. In this study, we investigated the effectiveness of three bedside cognitive tests in consecutive patients with PD without postural instability. Of the 119 patients, 39 experienced falls during the follow-up period. Of the bedside cognitive assessment methods examined, only the Montreal Cognitive Assessment (MoCA) score was significantly lower in the group of fallers than in the group of non-fallers. This result suggests that the MoCA is effective as a bedside test for evaluating the risk of falls.